1. Field of the Invention
The present invention relates to cooling systems for motor vehicles. In particular, the present invention relates to a vehicle hood for enclosing an engine and related cooling system. The hood includes a screened cooling air intake and an air baffle for directing ambient cooling air to a radiator. Sealing surfaces of the hood prevent engine-heated air from being used to cool the radiator and help isolate engine noise.
2. Description of Related Art
Conventional hoods or shrouds on small vehicles such as front mounted mowers typically enclose an engine, cooling system, and other vehicle components. Such vehicles commonly utilize liquid cooled internal combustion engines which generate heat during their operation. Liquid-cooled engines employ pressurized coolant circulated through the engine to absorb heat. The heated coolant is subsequently passed through a heat exchanger such as a radiator to dissipate heat from the coolant to the atmosphere, after which the coolant is recirculated to the engine for further cooling. As the coolant is passed through the heat exchanger, air flows through the heat exchanger to absorb heat and carry it out into the atmosphere. Air is commonly drawn or propelled through the radiator by use of a fan.
The capacity of a cooling system in such a vehicle depends on many factors including the velocity and volume of air flowing through the heat exchanger, as well as the distribution of the air flow over the available heat exchange surface of the radiator. Since these vehicles are often used in cutting grass and other vegetation, the air used to cool the radiator is frequently contaminated with dust, grass clippings and similar debris. Typically, such vehicles will include a grille or grilles on their hoods to reduce debris present in the cooling air while allowing the air to pass into the area enclosed by the hood to cool the engine by interaction with the radiator. However, a further problem can occur when the cooling air is drawn in around the engine. This air can become heated by the engine and cooling of the radiator can become more difficult. When ducting structures are used to keep the air cool by guiding it around the engine and to the radiator, they can interfere with access to engine components for service and/or maintenance.
It would therefore be desirable to provide an engine enclosure for a liquid cooled engine which can provide a sufficient supply of air to cool the radiator and engine coolant circulating through it. It would also be desirable to provide the supply of air without the flow being interrupted or compromised due to blockages caused by dust, grass clippings or similar debris. It would further be desirable to prevent the air supply from being heated by the engine as it is drawn to and passed through the radiator. Also, it would be desirable that the air heated by passing through the radiator be exhausted in a manner that would not affect the operator or lawn being cut. It would be desirable as well to provide an air intake structure that would not interfere with servicing and/or maintenance of the engine and its components. Lastly, it would be desirable to provide an air intake structure that would serve to minimize the engine noise escaping from the engine compartment.
It would also be desirable to provide a single piece hood that encloses the top and sides of the component compartment area, and which is provided with baffles defining air passages to allow for cooling air and carburetion air to pass therethrough. It would further be desirable to provide a hood capable of being made of a composite material so as to simplify the manufacturing, assembly, maintenance and styling needs associated with the hood.